Application Note 152
July 2016
Power System Management Addressing
Michael Jones Introduction
The foundation of all PMBus applications, including LTCВ®
Power System Management (PSM), is the ability for the
PMBus master (system host) to communicate with all
PMBus slaves (PSM controllers, PSM managers, PSM
ВµModulesВ®, and PMBus monolithic devices) on the bus.
Every slave on the bus must have a unique address that
does not conflict with other devices.
The bus master must also be able to communicate with
PSM slaves in a few less than obvious situations: Address discovery Global actions Multiphase rails Invalid NVM Bus MUXes
Device addressing is achieved with a combination of base
registers plus external address select (ASEL) pins, as well
as special global, rail, ARA, and other special addresses.
This Application Note will present the fundamental design
principles underlying the LTC PSM family, details on product
family differences, as well practical examples and advice.
Special cases, such as invalid NVM, will also be discussed.
The benefit to you is a design that works on day one, and
works even when things go wrong. For example, if you
are writing to the NVM with LTpowerPlayв„ў, and power is …